Don't print empty responses

This includes dicts/lists/strings and anything
that evaluates to False.
Merge branch 'empty-response' into develop

* empty-response:
  Don't print empty responses
Extract split_on_commas into a utils module
Promote top level args to put-metric-data
Rename renames test to utils
Add util code for validating mutex groups
Update RDS example to use full option names

We don't support the short option names.

Fixes #235.
Fix --no-paginate to check for None values

Basically --no-paginate didn't work.  If you don't check for None
values, the arg object will insert args that don't actually exist in the
op model which botocore will (correctly) complain about.

Added an integration test as well as a unit test to catch this
in the future.
Merge branch 'fix-no-paginate-arg' into develop

* fix-no-paginate-arg:
  Fix --no-paginate to check for None values
Add comment about default value

As per review feedback.
Merge branch 'put-metric-data' into develop

* put-metric-data:
  Add comment about default value
  Add util code for validating mutex groups
  Rename renames test to utils
  Promote top level args to put-metric-data
  Extract split_on_commas into a utils module
Update handler for ses customization and add an nargs param to CustomArgument constructor.
Adding customization code for ses send-email as well as unit tests.
Improve doc strings, change nargs from * -> + for address options.
Merge branch 'fix-235' into develop

* fix-235:
  Update RDS example to use full option names
Customization to make it easier to deal with bootstrapping data from iam create-virtual-mfa-device call.
Fix and use FileArgument class.  Add test for unwritable outfile.
Merge branch 'iam-vmfa' of git://github.com/garnaat/aws-cli into garnaat-iam-vmfa
Fix parsing issue with quoted shorthand values

Fixes #174.  The problem was that if multiple equal
signs are present in a key/val pair (if the value has
an equal sign) then we would hit this error.  I double
checked the other parsing parts of argprocess, they all
properly use '.split("=", 1)'.

This also required updated the csv parsing to handle the
case where you quote a value without commas, e.g. foo="bar=baz".
Unify boolean arg behavior

Regardless of whether or not an option is required:

* If you explicitly set the value, `--enable-foo`, we
  add a True value to the params dict.
* If the explicitly set the negative value, `--no-enable-foo`,
  we add a False value to the params dict.
* If you omit the value, we don't add anything to the params dict.

Fixes #161